The effectiveness of green roofs measured by nutrient, total suspended solids and total organic carbon content

Green roofs are a useful tool to retain heat, limit the heat island effect and improve the sustainability of cities, but their effectiveness of nutrient retention is still up for debate. This is due to the fact that their ability to retain nutrients is highly dependent on growing media, plant type, climate, and rainfall amount and intensity. This study aims to understand both planted and unplanted aqualok, planted and unplanted lava rock, and aqualok bioswales ability to retain nutrients at various location in the District of Columbia. While the green roofs ability to retain nutrients varied at the locations, overall the planted aqualok and lava rock roofs were able to retain both forms of nitrogen, but other roofs released more nutrients than present in rainfall. This is not to say that green roofs should not be utilized, as many released less nutrients than current asphalt roofs.